The increasing imperative to find what works in health services has meant a rise in research trialing interventions deemed 'complex'. While the strength of these interventions comes from taking a 'whole of problem' approach using multiple and inter-linking strategies, ways of examining implementation are under-explored. Building sustainability is an important part of implementing complex intervention research, but this too has received little exploration in the implementation literature. This paper explores issues of implementation and sustainability by examining the case of PRISM (Program of Resources, Information and Support for Mothers), a community randomised trial in Victoria, Australia aimed at improving maternal health and wellbeing. It examines documents placed on the project website. Three groups of documents relating to implementation of the intervention were examined - implementation reports, media reports and community newsletters. Analysing these documents allowed a focus on the 'work' of the intervention - who does the work and what activities comprise the work - in order to examine implementation as it relates to sustainability. Document analysis provides a useful way of considering implementation and sustainability of complex intervention research. It can 'value add' to findings from process evaluation and extend our understanding of an intervention beyond outcome measures. Analysis of the documents in this case provides insights into why sustainability of an intervention may be difficult to achieve during implementation.